<!DOCTYPE html>
<html lang="zh_CN">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<button id="btn">点击我弹出一个提示框</button>
</body>
<script type="text/javascript">


    var oBtn = document.getElementById('btn');

    oBtn.onclick = function () {
        console.log('点击事件被执行了');
    }

    var a = 1;
    var b = 2;
    var c = a + b;

    console.log(c);


</script>

</html>
